[HBASE-8805] Add online configeration supporting and corresponding testcases

Summary: HRegion implements ConfigurationObserver, register/deregister from HRegionServer.configurationManager, testcases

Test Plan: Run testcase

Reviewers: gauravm, zelaine, liyintang

Reviewed By: liyintang

CC: mahesh, hbase-eng@

Differential Revision: https://phabricator.fb.com/D1067616

Task ID: 2977299

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1548981 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-9815] Fixing TestFlashbackQuery and TestHeapSize.

Author: manukranthk

Summary: The allocate should be called before returning the histogram. For TestHeapSize, the number of references in the Store is increased by 1 so, FIXED_OVERHEAD needs to be bumped up by 1.

Test Plan: Ensuring the unit tests pass.

Reviewers: adela, liyintang, daviddeng

Reviewed By: adela

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1078262

Task ID: 3297578

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1548982 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-10083] Better error handling for the compound bloom filter

Summary:
When RegionServer failed to load a bloom block from HDFS due to any timeout or other reasons, it threw out the exception and disable the entire bloom filter for this HFile. This behavior does not make too much sense, especially for the compound bloom filter.
Instead of disabling the bloom filter for the entire file, it could just return a potentially false positive result (true) and keep the bloom filter available.

Test Plan: will run through all the unit tests and shadow testing for Altair.

Reviewers: aaiyer, rshroff

Reviewed By: aaiyer

CC: hbase-eng@, hbase-dev@

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1548984 13f79535-47bb-0310-9956-ffa450edef68